Temperature dependence of a niti shape memory alloy's superelastic behavior at a high strain rate

Abstract

The temperature dependence of the dynamic compressive stress-strain behavior of a NiTi shape memory alloy (SMA) has been determined at a strain rate of 4.35x102 s-1 with a split Hopkinson pressure bar (SHPB) modified for obtaining the dynamic stress-strain loops at constant strain rates. The environmental temperature was varied from 0 to 50 C, where the SMA exhibits superelastic behavior through stress-induced martensite (SIM). Experimental results show that both the loading and unloading portions of the stress-strain loop are significantly temperature dependent. Shape memory effect below the austenite finish transition temperature, A f, and superelastic behavior above A f are also observed at the high strain rate.